Strange non-chaotic attractors in spin valve systems
Abstract
The current-driven magnetization dynamics in spin torque oscillators is investigated because of its high potential for high-frequency applications. The system consists of a pinned layer with a fixed magnetization and a single-domain free layer, such that it is governed by the Landau-Lifshitz-Gilbert-Slonczewski equation. In particular, we study the effect of a time-dependent quasi-periodic current. We numerically characterize the dynamical behavior of the system by monitoring the Lyapunov exponents, and by calculating the Fourier spectra. We find a rather complicated landscape of sometimes closely intermingled chaotic and non-chaotic areas in the parameters space. Finally, we compute a phase diagram of the existence of the strange non-chaotic attractors.
- Publication:
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Journal of Magnetism and Magnetic Materials
- Pub Date:
- August 2018
- DOI:
- 10.1016/j.jmmm.2018.04.024
- Bibcode:
- 2018JMMM..460..320C
- Keywords:
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- Magnetization dynamics;
- Strange non-chaotic attractors;
- Chaos